1. Field of the Invention
The present invention relates generally to pipe interruption fittings which are used for temporarily interrupting fluid, such as gas, water and sewage, chemicals, etc., flowing towards concerned portions of pipes while maintenance work, such as replacement or repair of pipes or connection of branch pipes, is conducted at the concerned portions of the pipes and, more particularly, to a pipe interruption fitting, which has a structure such that, after a pipe has been interrupted and pipe maintenance or repair work has been completed, an unnecessary flange is removed from the fitting, so that the fitting and the periphery can be easily processed for heat insulation and corrosion resistance treatment, and, as well, even if excavation work is conducted adjacent to the pipe interruption fitting, because there is no flange that can be caught by an excavator, the pipe interruption fitting is prevented from being damaged by the excavator.
2. Description of the Related Art
Recently, city gas is supplied to most dwellings. Furthermore, most buildings and dwellings use city gas as fuel for heating. Therefore, in most cities or villages where people dwell, gas pipes for supplying city gas from city gas supply plants are laid in the ground like webs.
Furthermore, in most cities or villages, water supply and sewage pipes as well as gas pipes are installed in the ground. Around plants for manufacturing chemicals, pipes for carrying chemicals are installed in the ground.
When it is required to repair or replace such a pipe, such as a gas pipe, a water or sewage pipe or a chemical pipe, with a new one, or when it is required to connect a branch pipe to a main pipe, pipe interruption fittings are used for interrupting an upstream position and a downstream position of a concerned portion requiring maintenance work (hereinafter, referred as “maintenance requiring portion”) of the pipe.
That is, the maintenance requiring portion of the pipe is interrupted at an upstream position thereof, and is also interrupted at a downstream position thereof to prevent gas, water or sewage from backflowing towards the maintenance requiring portion.
Furthermore, it may be required to continuously supply gas or water during pipe maintenance work in order to prevent users from being inconvenienced. In this case, a bypass pipe may be temporarily provided between the upstream position and the downstream position of the maintenance requiring portion of the main pipe to continuously supply fluid, such as gas or water.
A representative example of conventional pipe interruption fittings is shown in FIG. 1. As shown in FIG. 1, in a conventional pipe interruption fitting 3, a flange 2 is welded to an upper end of a vertical pipe 1, and a lower end of the vertical pipe 1 has a shape corresponding to the curvature of the pipe to be interrupted.
The process of interrupting the pipe using the conventional pipe interruption fitting 3 having the above-mentioned structure will be described herein below.
(1) As shown in FIG. 2, the vertical pipe 1 is welded to the pipe 4 after the lower end of the vertical pipe 1 is brought into contact with the pipe 4.
(2) After an intermediate cutout valve 5 is coupled to the upper end of the flange 2, a boring machine 6 is mounted on an upper end of the intermediate cutout valve 5.
(3) As shown in FIG. 3, the intermediate cutout valve 5 is opened, and a boring tip 6a of the boring machine 6 is moved to the pipe 4 and is rotated, thus boring a hole in the pipe 4.
(4) The boring tip 6a of the boring machine 6 and a cut part of the pipe 4 are pulled up into the main body of the boring machine 6. Here, a device, which pulls the boring tip 6a and the cut part of the pipe 4 upwards, is provided in the boring machine 6, but this is not related to the present invention, therefore further explanation thereof will be omitted.
(5) The intermediate cutout valve 5 is dosed, and the boring machine 6 is removed from the intermediate cutout valve 5.
(6) As shown in FIG. 4, a stopple machine 7 is mounted to the intermediate cutout valve 5.
(7) The intermediate cutout valve 5 is again opened, and a stopple 7a of the stopple machine 7 is moved downwards into the pipe 4 such that the stopple 7a interrupts fluid in the pipe 4. The stopple machine 7 has a structure such that the stopple 7a is perpendicularly bent after being inserted into the pipe 4, but this is a well known technique, therefore further explanation is deemed unnecessary.
(8) As such, in the state in which the pipe 4 is interrupted at each of the upstream and downstream positions of the maintenance requiring portion of the pipe 4 using the stopple 7a, maintenance work is conducted. After the maintenance work has been completed, the stopple 7a of the stopple machine 7 is pulled up into the main body of the stopple machine 7, the intermediate cutout valve 5 is dosed, and the stopple machine 7 is removed from the intermediate cutout valve 5.
However, the conventional pipe interruption fitting 3, which is used for temporarily interrupting fluid flow in the pipe through the above-mentioned processes when pipe maintenance work is required, has the following problems.
(1) The lower end of the vertical pipe 1 of the pipe interruption fitting 3 must be cut into a shape corresponding to the curvature of the pipe 4. Therefore, a lot of time is required to shape the lower end of the vertical pipe 1 in the process of manufacturing the pipe interruption fitting 3. Furthermore, because the vertical pipe 1 of the pipe interruption fitting 3 is in edge contact with the pipe 4, load is concentrated on one part of the pipe 4, thereby it is difficult to conduct the welding work. As well, during use, there is a likelihood of cracks occurring at the junction of the vertical pipe 1 and the pipe 4, which are in edge contact with each other.
(2) Even after fluid flow in the pipe 4 has been interrupted using the pipe interruption fitting 3 and the pipe maintenance work has been completed, the intermediate cutout valve 5 must maintain the state of being coupled to the upper end of the pipe interruption fitting 3. The reason is that, because the pipe interruption fitting 3 is filled with gas after the work of boring the pipe 4 has been conducted, if the intermediate cutout valve 5 is removed, gas is discharged outside. Therefore, the expense of the pipe maintenance work increases due to the expensive intermediate cutout valve 5.
In an effort to overcome the above-mentioned problems with the pipe interruption fitting 3, another pipe interruption fitting, shown in FIG. 5, was proposed in Korean Utility Model Registration No. 0157683, which was registered on Jul. 3, 1999.
As shown in FIGS. 5 through 7, this pipe interruption fitting includes a vertical pipe 11, a flange 12, which is welded to an upper end of the vertical pipe 11, and a plug 13, which is screwed into an opening, which is formed at a central position in the flange 12. The pipe interruption fitting further includes a cover plate 14, which covers the flange 12 and the plug 13, and a reinforcing plate 15, which is welded to the lower end of the vertical pipe 11, and which has a circumferential inner surface having the same curvature as that of the circumferential outer surface of the pipe.
Furthermore, a sealing member 19 is interposed between the flange 12 and the plug 13, which is screwed into the flange 12, thus preventing fluid from leaking therebetween.
The flange 12 and the cover plate 14 are coupled to each other using bolts 17 and nuts 18. A gasket 20 is interposed between the flange 12 and the cover plate 14 to more reliably prevent fluid from leaking.
Furthermore, a lower reinforcing plate 16 is additionally provided to reinforce the pipe more reliably.
The method of using the pipe interruption fitting having the above-mentioned construction is presented below. The upper reinforcing plate 15 and the lower reinforcing plate 16 are respectively welded to an upper portion and a lower portion of the pipe at the position at which interruption of fluid flow is required. Here, because the reinforcing plates 15 and 16 contact a relatively large area of the pipe, preventing only a small part of the pipe from being affected by force, the process of welding the upper and lower reinforcing plates 15 and 16 to the pipe can be stably conducted, and the pipe interruption fitting can maintain a stable installation state after all processes have been completed. The lower reinforcing plate 16 supports the lower portion of the pipe 4, so that the pipe 4 is prevented from being bent by the weight of the intermediate cutout valve 5 and a boring machine 6.
In a state in which the plug 13 is removed, the intermediate cutout valve 15 is coupled to the flange 12, and the boring machine 6 is mounted to the upper end of the intermediate cutout valve 15.
The intermediate cutout valve 5 is thereafter opened, and a hole is bored through the pipe 4 using a boring tip 6a of the boring machine 6. After the hole has been bored, the cut part of the pipe and the boring tip 6a of the boring machine 6 are moved upwards. Thereafter, the intermediate cutout valve 5 is dosed, the boring machine 6 is removed, and a stopple machine 7 is mounted on the intermediate cutout valve 5.
Subsequently, the intermediate cutout valve 5 is again opened, and a stopple 7a of the stopple machine 7 is moved downwards to close the pipe 4, thus blocking fluid flow.
After the desired pipe maintenance work has been completed, the stopple 7a of the stopple machine 7 is moved upwards and the intermediate cutout valve 5 is closed. Thereafter, the stopple machine 7 is removed from the intermediate cutout valve 5.
Subsequently, a plug adaptor 6b is coupled to an end of a rod of the boring machine 6, and the plug 13 is fitted over the plug adaptor 6b. In this state, the boring machine 6 is mounted to the intermediate cutout valve 5. Thereafter, the intermediate cutout valve 5 is opened, and the plug 13 is screwed to the opening, which is formed at the central position in the flange 12. Because the sealing member 19 is fitted over the plug 13, the junction between the flange 12 and the plug 13 can be reliably sealed after the plug 13 has been assembled with the flange 12. Thereafter, the boring machine 6 and the intermediate cutout valve 5 are removed.
Finally, the cover plate 14 is coupled to the flange 12 using the bolts 17 and the nuts 18. Then the gasket 20 is interposed between the flange 12 and the cover plate 14. At this time, all of the processes have been completed.
However, in this pipe interruption fitting, there is a problem in that, because the flange 12 protrudes in a horizontal direction, when a process of covering the pipe interruption fitting using a patch or the like for heat insulation and corrosion resistance treatment is conducted, the flange 12 inconveniences a user. As well, when excavation work is conducted adjacent to the pipe interruption fitting, there is a probability of damaging the pipe interruption fitting due to an excavator catching the flange. Furthermore, because the plug 13 is screwed to the flange 12, there is a disadvantage in that the plug 13 must be rotated several times.